Method of securing bundles of bristles in the bodies of brushes



Patented Sept. 29, 1931 UNI'IED STATES PATENT OFFICE KARL DBESSLER, OF GROSS SCHONA U GERIMZANY, ASSIGNOR T ISRAL MOSES LERCH, OF LEIPZIG, GERMANY METEOD OF SECU'RING BUNDLES OI BRIS'ILES IN 'IHE BODIES OF IBBUSHES Applieation filed April 29, 1927, Serial No. 187,674, and in Germany May 7, 1926.

This invention relates -to a prooess or securing bristles collected together in the form of bundles in the body of a brush for the purpse of manufacturing brushes and it relates particularly to the manufaeture of brushes in whieh the parts which receive of the bundle hole as the tool advancesfurther, as is shown in Fig. 7.

This may"be aehieved f or example by eausing the edge of the bundle holes to be removed by substantially rounding er deg5 pressing the same 01 by providing annular projeetions a1ound the bundle holes, whilst at the same time correspondingly rounding ofi' their edges. The result of the process according to the present invention is that on application of pressure the material of the brush body whch is malleable, forces the metal to constrict the bundle hole. In this way a constriction of the bundle hole which is substantially uniform throughout is obtained. The edge of the hole is not sharp, so that the bristle bundles are not subjected to the risk of damage by shar edges whlst being firmly and tightly hel in order that liquid or dirt may not be able to penetrate into the body of the brush.

Fig. 1 is a fragmentary transverse elevation of a brush blank;

Fig. 2 is a fragmentary transverse elevaton of the same, showing the bristles inserted in the bundle hole;

Fig. 3 is a section si milar to Figures 1 and 2, showing the acti on of the pressure tool Fig. 1 is a fragmentary sectional elevation of a modified form of brush blank;

Fig. 5 is a fragmentary sectional elevation of the same, showing the bristles in plaee;

Fig. 6 is a section similar to Figures 4 and1 5 showing the aetion of the pressure too Fig.- 7 is a fragmentary transverse sectional elevation of a finished brush immediately before the pressure tool is removed.

Two examples of methods of carrying out the invention are illustrated in the accompanying drawings.

Figures 1 and 4 illustrate the body of a brush having bundle holes 0 for the insertion of bundles of bristles, the form indicated by 1 having a substantially rounded portion d atthe edge of the bundle hole c, whilst tha.t designated II has an annular projection d surrounding the bundle hole.

Figures 2 and 5 show that the bundle f together with an anchoring device e has been threaded through the pressure tool b illustrated in the drawings and previously used in other processes. After the needle has been withdrawn the, pressure tool exerts a. pressure on the brush body en as shown in Figures 3 and 6, and by means of ts wide and flat pressure surface it compresses the material of the brush body in an annular formation around the hole, whereby the latter under-goes a deeply penetrating eonstrict1on whlst at the same time a new and sli htly rounded edge is formed around the ho e, the said edge not damaging the bristles. Thereupon the pressure tool 1) is raised and sets free the bundle f which latter is now quite tightly enclosed and held in the hole 0 in the example designated I the bundle is surrounded. by an annular depression g corresponding tothe pressure surfaee of the pressure tool, whilst in the example designatedfl it is snrrounded by a flat surface g. Figure 7 shows en a much enlarged scale the operation of the pressure tool. After the bundle f has been inserted together with an anchoring device e through into the hole 0 by means of a needle not the pressure tool b into the bundle hole c in the brush body a the pressure tool b with its flat pressure surface compresses the ma terial surrounding the edge of the hole d in :1 downward direction, this matorial being displncod in the direction of the arrows towamls the interior of the hole 0, thus cnusing a doop going constriction of the bundlo hole; whlst the walls of the hole llllllll smooth and a new and roundod edge is formcd around the hole.

Hnving now particularly doscribe l aml uscvrtaincd the nature of my said invcntion und in wlmt nummer the sumo is to be porl'ormud, I decluro tlmt what I claim is 1- 1. A process for the manufacture of bristle brushes which consists in forming a multiplcity of sockets in a piece of metal the thickness of which is ioitor than the depth of the sockots and sullicient t0 adapt it for use as a brush body, each of suid sockets having a woll rounded edge, inserting a. bundle of bristles in each of said sockets, and applying to an annular surface around ouch socket pressure suficient to cause luteral displacemont of metul substuntiully throughout the depth of the socket, and thereby form a socket entirely below the plane of the upper surfuce of the body which socket lms u rounded edge and securcly grips tho bundle of bristles throughout its depth.

2. A process fox the manfacture of bristlo brushes which consists in forming a multiplicity of sockets in a piece of metal the thickncss of which is greuter than the depth of the sockets and suflicient to adapt it for use as a brush body, each of suid sockets having a well rounded edgo surrounded by a raised annulus integml with said body, inserting a. bundle of bristles in each of smid sockets, and applying to said unnulus pressure suflcient to cause contraction of the bore of the socket substantially throughouig its depth, und thereby form a socket entirely below the plane of the surfuce of the brush body, said socket having a rounded edge and being in gripping engagement with the bundle of bristles t noughoijt its depth.

In testimony whereof I have afiixed my signature.

KARL DRESSLER. 

